Studies of flows induced by Sub Boundary Layer Vortex Generators (SBVGs)

Ashill, P. R.; Fulker, J. L.; Hackett, K.

doi:10.2514/6.2002-968

Cited by 60 publications

(55 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Investigation in the cross-flow planes allowed to quantify the decay of streamwise vortex intensity. Among all the devices studied, the peak vorticity produced by ramped vane produces the strongest intensity and the slowest decay, confirming the conclusion from experiment in subsonic flow [42]. The ramped vane also yields the best performance in terms of separation reduction.…”

Section: Mvg and Incident Shock Wave Boundary Layer Interaction (Iswbsupporting

confidence: 72%

Micro Vortex Generators for Boundary Layer Control: Principles and Applications

Sun¹

2015

International Journal of Flow Control

View full text Add to dashboard Cite

This is the accepted version of the paper.This version of the publication may differ from the final published version. Permanent repository link AbstractA review is given to the major developments in the boundary layer control by means of micro vortex generator (MVG). The appearance of MVG dates back to about three decades from the present review and this class of device rapidly spreads as an efficient and robust boundary layer control strategy for flows with separation in particular. Substantial successful applications of MVG have been achieved in subsonic flows and its application into supersonic flow is under progressive development, which requires the current status and capability of MVG to be reviewed. The fundamental aspects of MVG are first summarized, including its working principle and various geometries. Understanding of the fluid mechanics involved in the wake of a MVG device is of uppermost importance: the timeaveraged and instantaneous wakes are discussed respectively. In the former, effects from the MVG geometry parameters are presented; while in the latter, focus is placed on the phenomenon associated with flow instability inside the wake. MVG's applications in the subsonic regime are discussed, which covers the fundamental flow separation investigations and studies to tackle several practical problems. The ongoing studies in supersonic regime dealing with shock wave boundary layer interaction (SWBLI) induced separation are reviewed later, where the presentation is organized according to different types of SWBLI with emphasis on the interaction region.

show abstract

Section: Mvg and Incident Shock Wave Boundary Layer Interaction (Iswbsupporting

confidence: 72%

Micro Vortex Generators for Boundary Layer Control: Principles and Applications

Sun¹

2015

International Journal of Flow Control

View full text Add to dashboard Cite

show abstract

“…While the above-referenced studies have vortex generators that have profiles projecting out of the boundary layers, there have been a few studies that have used low-profile vortex generators (VG) which are submerged within the boundary layers (Ashill et al, 2002 andYao et al, 2002). These low profile vortex generators improve the ability of the boundary layer to resist flow separation with relatively low drag penalty since they are immersed in flows of low dynamic pressure.…”

Section: Embedded Vortex Flowsmentioning

confidence: 99%

Structure of 2-D and 3-D Turbulent Boundary Layers with Sparsely Distributed Roughness Elements

George¹

2005

View full text Add to dashboard Cite

The present study deals with the effects of sparsely distributed three-dimensional elements on two-dimensional (2-D) and three-dimensional (3-D) turbulent boundary layers (TBL) such as those that occur on submarines, ship hulls, etc. This study was achieved in three parts: Part 1 dealt with the cylinders when placed individually in the turbulent boundary layers, thereby considering the effect of a single perturbation on the TBL; Part 2 considered the effects when the same individual elements were placed in a sparse and regular distribution, thus studying the response of the flow to a sequence of perturbations; and in Part 3, the distributions were subjected to 3-D turbulent boundary layers, thus examining the effects of streamwise and spanwise pressure gradients on the same perturbed flows as considered in Part 2. The 3-D turbulent boundary layers were generated by an idealized wing-body junction flow.Detailed 3-velocity-component Laser-Doppler Velocimetry (LDV) and other measurements were carried out to understand and describe the rough-wall flow structure. The measurements include mean velocities, turbulence quantities (Reynolds stresses and triple products), skin friction, surface pressure and oil flow visualizations in 2-D and 3-D rough-wall flows for Reynolds numbers, based on momentum thickness, greater than 7000. Very uniform circular cylindrical roughness elements of 0.38mm, 0.76mm and 1.52mm height (k) were used in square and diagonal patterns, yielding six different roughness geometries of rough-wall surface. For the 2-D rough-wall flows, the roughness Reynolds numbers, + k , based on the element height (k) and the friction velocity ( τ U ), range from 26 to 131. Results for the 2-D rough-wall flows reveal that the velocity-defect law is similar for both smooth and rough surfaces, and the semi-logarithmic velocity-distribution curve is shifted by an amountdepending on the height of the roughness element, showing thatis a function of + k and the wall geometry. For the 3-D flows, the data show that the surface pressure gradient is not strongly influenced by the roughness elements. Higher roughness elements cause greater turbulence intensities near the wall, which cause the pressure-driven mean flow three-dimensionality to propagate or diffuse more rapidly from the wall region. In general, for both 2-D and 3-D rough-wall TBL, the differences between the two roughness patterns (straight and diagonal), as regards the mean velocities and the Reynolds stresses, are limited to about 3 roughness element heights from the wall.For the single elements, the values of + k range from 23 to 92. The study on single elements revealed that the separated shear layers emanating from the top of the elements form a pair of counter rotating vortices that dominate the downstream flow structure. These vortices, termed as the roughness top vortex structure (RTVS), in conjunction with the mean flow, forced over and around the elements, are responsible for the production of large Reynolds stresses in the neighborhood of th...

show abstract

“…Vortex generators technology is a much more mature, diverse, and far reaching in acceptance [61], see figure 17. Vortex generators were initially developed and applied to aircraft but have been accepted throughout the transportation and Industrial areas.…”

Section: Drag Reduction Technologiesmentioning

confidence: 99%

Impact of Advanced Aerodynamic Technology on Transportation Energy Consumption

Wood¹

2004

SAE Technical Paper Series

View full text Add to dashboard Cite

An assessment of the role of fluid dynamic resistance and/or aerodynamic drag and the relationship to energy use in the United States is presented. Existing data indicates that 16% of the total energy consumed in the United States is used to overcome aerodynamic drag in transportation systems. Application of existing pressure drag reduction technologies to all ground vehicles within the United States will reduce yearly energy costs by 20 billion dollars.

show abstract

Studies of flows induced by Sub Boundary Layer Vortex Generators (SBVGs)

Cited by 60 publications

References 5 publications

Micro Vortex Generators for Boundary Layer Control: Principles and Applications

Micro Vortex Generators for Boundary Layer Control: Principles and Applications

Structure of 2-D and 3-D Turbulent Boundary Layers with Sparsely Distributed Roughness Elements

Impact of Advanced Aerodynamic Technology on Transportation Energy Consumption

Contact Info

Product

Resources

About